I'm not sure if this should be posted here, or in JK electrical... but here goes.

This morning the wife called and said the jeep was running rough. And in the afternoon, the engine light came on. I borrowed my step fathers code reader. It showed 2 codes: random multiple misfires & ignition coil. So im thinking.. whaaaat!? My $190 screamin demon performance coil has taken a dump after 9 months of use?!

So i swapped in my OE coil pack. Still throwing codes, still running rough, still sounds like a... i dunno what, but it sounds bad. Swapped in my OE wires. Again with the codes and rough idle.

I will change the plugs this weekend. If this doesnt take care of the problem.. well... i really cant afford a trip to the dealership right now.

Plugs, coil & wires all less than a year old. I should also mention that in the past few months, usually after driving for a bit, and then stopping to get gas or something, the jeep wont start. Dash lights up, has power.. no click, no clunk, no crank. Nothing. Fiddle with it, try a few time and she starts. I was thinking maybe clutch position sensor? But now with the misfire, i thought coil pack for sure.. but after swapping out the coil? I have no clue. Crank position sensor? I have one laying around somewhere.. dont know where..

Any insight is appreciated.

 

Check and see if the battery is charging and check your grounds.

 

Post the code numbers. Makes it easier to look stuff up.

 

I took a sick day tomorrow... I'll get back into it in the AM. Will post codes, check grounds and alternator. I have a spare alternator also, but i think its stored in my friends garage.

 

P2305 - Ignition Coil 2 Secondary Circuit- Insufficient Ionization
P0300 - Random Multiple Misfires

 

Misfires and rough running are sometimes hard to diagnose because so many things can cause it.

Here is some info on the codes you have. (If you plan to do any of the troubleshooting listed below, pm me.)

P2305-IGNITION COIL 2 SECONDARY CIRCUIT- INSUFFICIENT IONIZATION


When Monitored:
Engine running and battery voltage greater than 10 volts.

Set Condition:
If PCM detects that the secondary ignition burn time is incorrect, too short, or not present, an error is detected. One Trip Fault. Three good trips to turn off the MIL.

Possible Causes

ASD OUTPUT CIRCUIT

COIL CONTROL 2 CIRCUIT OPEN

COIL CONTROL 2 CIRCUIT SHORTED TO GROUND

COIL

POWERTRAIN CONTROL MODULE (PCM)




P0300-MULTIPLE CYLINDER MISFIRE


When Monitored:
Any time the engine is running, and the adaptive numerator has been successfully updated.

Set Condition:
The threshold to set the fault is application specific; it is tied to the level of misfire that will cause emissions to increase to 1.5 times the standard or in some cases 1%. It is always a two trip fault above the calibrated RPM. It takes 1 soft fail to set a malfunction and two trips to set the MIL. Three good trips to turn off the MIL.

Possible Causes

ASD RELAY OUTPUT CIRCUIT

INJECTOR CONTROL CIRCUIT

COIL CONTROL CIRCUIT

IGNITION WIRE

SPARK PLUG

IGNITION COIL

FUEL PUMP INLET STRAINER PLUGGED

RESTRICTED FUEL SUPPLY LINE

FUEL PUMP MODULE

FUEL PRESSURE LEAK DOWN

FUEL INJECTOR

ENGINE MECHANICAL

POWERTRAIN CONTROL MODULE (PCM)

 

No spark in 2 cylinders.
Not firing injectors in the same 2 cylinders.
False code from key.

Problem: bad PCM
Solution: 4 days @ dealership + $592 :(